[PATCH 2/8] HID: core: store the collections as a basic tree

From: Peter Hutterer
Date: Thu Nov 22 2018 - 01:35:02 EST


For each collection parsed, store a pointer to the parent collection
(if any). This makes it a lot easier to look up which collection(s)
any given item is part of

Signed-off-by: Peter Hutterer <peter.hutterer@xxxxxxxxx>
---
drivers/hid/hid-core.c | 4 ++++
include/linux/hid.h | 2 ++
2 files changed, 6 insertions(+)

diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
index 5bec9244c45b..43d488a45120 100644
--- a/drivers/hid/hid-core.c
+++ b/drivers/hid/hid-core.c
@@ -172,6 +172,8 @@ static int open_collection(struct hid_parser *parser, unsigned type)
collection->type = type;
collection->usage = usage;
collection->level = parser->collection_stack_ptr - 1;
+ collection->parent = parser->active_collection;
+ parser->active_collection = collection;

if (type == HID_COLLECTION_APPLICATION)
parser->device->maxapplication++;
@@ -190,6 +192,8 @@ static int close_collection(struct hid_parser *parser)
return -EINVAL;
}
parser->collection_stack_ptr--;
+ if (parser->active_collection)
+ parser->active_collection = parser->active_collection->parent;
return 0;
}

diff --git a/include/linux/hid.h b/include/linux/hid.h
index a355d61940f2..fdfda898656c 100644
--- a/include/linux/hid.h
+++ b/include/linux/hid.h
@@ -427,6 +427,7 @@ struct hid_local {
*/

struct hid_collection {
+ struct hid_collection *parent;
unsigned type;
unsigned usage;
unsigned level;
@@ -650,6 +651,7 @@ struct hid_parser {
unsigned int *collection_stack;
unsigned int collection_stack_ptr;
unsigned int collection_stack_size;
+ struct hid_collection *active_collection;
struct hid_device *device;
unsigned int scan_flags;
};
--
2.19.1